Adolescent exposure to violence, either as a witness or victim, is increasingly common and associated with a wide range of negative outcomes for youth, including increased likelihood of engaging in HIV/AIDS risk behaviors, such as low rates of condom use, having sex with multiple partners, and engaging in sexual behaviors while under the influence of alcohol or other substances. The public health importance of research to date on violence exposure and HIV/AIDS risk behaviors should not be minimized;however, several methodologicallimitations of this research, most notably the reliance on retrospective, cross- sectional, or short-term longitudinal designs, as well as the narrow focus on only one type of violence exposure or one HIV/AIDS risk behavior, significantly limit the policy implications of this work for HIV/AIDS prevention efforts. Utilizing advances in quantitative methods, in combination with the methodological rigor of the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN), a set of collaborating child abuse and neglect projects following 1,354 children in 5 locations acrossthe United States, the proposed K01 project aims to examine different developmental trajectories of violence exposure among maltreated youth, the extent to which specific trajectories better predict levels of involvement in HIV/AIDS risk behaviors in adolescence, and the role of contextual variables in moderating these trajectories. In turn, findings from the proposed analyses,as well as feedback from families of youth at-risk for violence exposure and the practitioners who serve them, will inform the development of a manualized HIV/AIDS prevention program targeting families of youth at high-risk for cumulative and chronic exposure to violence. The prevention program and associated manual will serve as the foundation for a subsequent grant application which will aim to pilot test the efficacy of the prevention program in a randomized clinical trial. Consistent with Health Protection Goals outlined by the Centers for Disease Control and Prevention, the research plan, training activities, and mentorship afforded by this K01 will increase the number of adolescents who are prepared to be healthy, safe, independent and productive members of society by addressing two major public issues of relevance for adolescent children, the rising rates of youth violence exposure in the U.S. and the associated risk for engaging in behaviors linked with the transmission of HIV/AIDS.